Source : Webster's Revised Unabridged Dictionary (1913)

Guan \Guan\ (gw[aum]n), n. ((Zo["o]l.)
   Any one of many species of large gallinaceous birds of
   Central and South America, belonging to {Penelope}, {Pipile},
   {Ortalis}, and allied genera. Several of the species are
   often domesticated.

Source : WordNet®

guan
     n : any of several large turkey-like game birds of the family
         Cracidae; native to jungles of tropical America;
         resembling the curassows and valued as food